1. Field of the Invention
This invention is related to the field of processors and, more particularly, to multiple processor cores (e.g. in chip multiprocessors) and responding to system requests from the multiple processor cores.
2. Description of the Related Art
Chip multiprocessors (CMPs) are becoming more popular in the present age. A CMP has two or more processor cores implemented on the same integrated circuit. CMPs may be a more efficient use of the millions of transistors that may be included on an integrated circuit than, for example, a more elaborate single processor.
Different CMPs may include different numbers of processor cores. For example, different models of a CMP product line may have different numbers of processor cores. Thus, a given “slot” for a CMP in a computer system may have differing numbers of processor cores dependent on which particular CMP is installed in that slot. In some cases, the number of processor cores affects the operation of the computer system. For example, when maintaining cache coherency in the system, probes are transmitted to determine if any caches are storing a cache block that is to be accessed by a given processor core. Typically, each of the other processor cores are probed, and provide a probe response. Thus, the total number of responses to the probe may be equal to the total number of processor cores. With different CMPs, the total number varies and thus the number of responses to expect varies. Similarly, system management messages may be transmitted to each of the processor cores. The number of responses indicating that the system management message has been serviced may vary depending on the number of processor cores in each CMP.